Introduction

Question 1

major forms of nitrogenous wastes

Answer 1

ammonia
urea
uric acid

Question 2

order of toxicity and solubility of nitrogenous wastes

Answer 2

ammonia > urea > uric acid

Question 3

process of excreting ammonia is called

Answer 3

ammonotelism

Question 4

which organisms are ammonotelic in nature

Answer 4

bony fishes, aquatic amphibians and aquatic insects

Question 5

how is ammonia excreted in ammonotelic organisms

Answer 5

diffusion across body surfaces or through gill surfaces in fish as ammonium ions
(since ammonia is readily soluble)

Question 6

ureotelic organisms

Answer 6

mammals, terrestrial amphibians, cartilaginous fishes

Question 7

how is urea excreted from ureotelic organisms

Answer 7

ammonia is converted to urea in liver and released into blood which is filtered and excreted out by kidneys

Question 8

in ureotelic organisms, some amount of urea may be retained in the kidney matrix, why

Answer 8

to maintain a desired osmolarity

Question 9

uricotelic organisms

Answer 9

reptiles, birds, land snails, insects

Question 10

how do uricotelic organisms excrete uric acid

Answer 10

in form of pellet or paste (minimun loss of water)

Question 11

excretory structure in platyhelminthes, rotifers, some annelids and the cephalochordate - amphioxus

Answer 11

protonephrida / flame cells

Question 12

what is the function of protonephrida

Answer 12

osmoregulation

Question 13

excretory structure of earthworms and other annelids

Answer 13

nephridia

Question 14

function of nephridia

Answer 14

remove nitrogenous waste and osmoregulation

Question 15

excretory structure of most insects including cockroaches

Answer 15

malpighian tubules

Question 16

function of malpighian tubes

Answer 16

removal of nitrogenous waste and osmoregulation

Question 17

excretory structures in crustaceans like prawns

Answer 17

antennal glands / green glands